Multiplex server for rust-analyzer, allows multiple LSP clients (editor
windows) to share a single rust-analyzer instance per cargo workspace.
The project has two binaries, ra-multiplex which is a thin wrapper that acts
like rust-analyzer but only connects to a TCP socket at 127.0.0.1:27631 and
pipes stdin and stdout through it.
The second binary ra-multiplex-server will listen on :27631 and spawn the
rust-analyzer server, depending on the working directory the ra-multiplex
client was spawned from it can reuse an already spawned rust-analyzer
instance. It detects workspace root as the furthermost ancestor directory
containing a Cargo.toml file. If the automatic workspace detection fails or
if you're not using rust-analyzer as a server you can create a marker file
.ra-multiplex-workspace-root in the directory you want to use as a workspace
root, the first ancestor directory containing this file will be used.
Because neither LSP nor rust-analyzer itself support multiple clients per
server ra-multiplex-server caches the handshake messages and modifies IDs of
requests & responses to track which response belongs to which client. Because
not all messages can be tracked this way it drops some, notably it drops any
requests from the server, this appears to not be a problem with
coc-rust-analyzer in neovim but YMMV.
If you have any problems you're welcome to open issues on this repository.
Build the project with
sh
$ cargo build --release
Run the ra-multiplex-server, make sure that rust-analyzer is in your
PATH:
sh
$ which rust-analyzer
/home/user/.cargo/bin/rust-analyzer
$ target/release/ra-multiplex-server
Configure your editor to use ra-multiplex as rust-analyzer, for example for
CoC in neovim edit ~/.config/nvim/coc-settings.json, add:
json
{
"rust-analyzer.serverPath": "/path/to/ra-multiplex"
}
Configuration is stored in a TOML file in your system's default configuration
directory, for example ~/.config/ra-multiplex/config.toml. If you're not sure
where that is on your system starting either ra-multiplex or
ra-multiplex-server without a config file present will print a warning with
the expected path.
Note that the configuration file is likely not necessary and ra-multiplex
should be usable with all defaults.
Example configuration file:
```toml
#
#
false for infinite timeoutinstance_timeout = 300 # after 5 minutes
gc_interval = 10 # every 10 seconds
#
#
listen = ["127.0.0.1", 27631] # localhost & some random unprivileged port
#
listenconnect = ["127.0.0.1", 27631] # same as listen
#
env_logger documentation here:log_filters = "info" ```
By default ra-multplex uses a rust-analyzer binary found in its $PATH as
the server. This can be overriden using the --ra-mux-server cli option or
RA_MUX_SERVER environment variable. You can usually configure one of these in
your editor configuration. If both are specified the cli option overrides the
environment variable.
For example with coc-clangd in CoC for neovim add to
~/.config/nvim/coc-settings.json:
json
{
"clangd.path": "/home/user/.cargo/bin/ra-multiplex",
"clangd.arguments": ["--ra-mux-server", "/usr/bin/clangd"]
}
Or to set a custom path for rust-analyzer with coc-rust-analyzer add to
~/.config/nvim/coc-settings.json:
json
{
"rust-analyzer.server.path": "/home/user/.cargo/bin/ra-multiplex",
"rust-analyzer.server.extraEnv": { "RA_MUX_SERVER": "/custom/path/rust-analyzer" }
}
If your editor configuration or plugin doesn't allow to add either you can
instead create a wrapper shell script and set it as the server path directly.
For example if coc-clangd didn't allow to pass additional arguments you'd
need a script like /usr/local/bin/clangd-proxy:
```sh
RAMUXSERVER=/usr/bin/clangd exec /home/user/.cargo/bin/ra-multiplex $@ ```
And configure the editor to use the wrapper script in
~/.config/nvim/coc-settings.json:
json
{
"clangd.path": "/usr/local/bin/clangd-proxy"
}